Luminaires are designed to produce a predetermined light distribution pattern in an area to be illuminated, such as in parking lots, along roadways, or in other areas requiring broad illumination of a surface. Luminaires generally include a housing or enclosure that supports a light socket, a high-intensity light source mounted in the socket, a light reflector mounted behind and/or around the light source and other electrical hardware necessary to energize the light source. The illumination pattern created by the luminaire is generally defined by the shape of the light reflector mounted in the luminiaire, as well as the position of the light source relative to the reflector. The reflector may form a partial enclosure about the source of light so that the inner surfaces of the reflector direct reflected light through an opening formed in a lower portion of the luminaire housing.
In the past, one-piece reflectors have been fabricated by molding or otherwise forming a flat piece of metal or other suitable reflective material into a desired reflector shape. The reflector may be formed by forming a sheet of reflective material between male and female dies that have cooperating three-dimensional shapes defining the reflector shape. Alternatively, the reflector may be formed by hydroforming the sheet of reflective material over a three-dimensional male form that defines the reflector shape as is well known in the art.
In another method, the reflector may be spun by contouring a sheet of reflective material over a revolving male mandrel with a pressure tool to conform the sheet to the shape of the mandrel. In yet another method of fabricating reflectors, the sheet of reflective material may be formed using a press brake or other forming machine that successively bends the sheet along predetermined fold lines into a series of planar facets that approximate a desired curved surface of the reflector.
Reflectors have also been fabricated from multiple sheets of reflective material that have been individually shaped and formed and then assembled together to form a reflector shape. The individual parts of the multi-component reflector have either been joined together through fastening hardware or other suitable structures prior to mounting the assembled reflector in a luminaire housing, or the reflector components have been mounted individually within the luminaire housing to form the three-dimensional reflector shape within the housing.
Forming the desired reflector shape using cooperating male and female dies has a drawback that the dies are relatively expensive to make and are difficult to modify if changes in the reflector shape are required. Moreover, the sheet of material may not draw easily and consistently to achieve the necessary depth and shape of the reflector during deep drawing formations. Hydroforming or spinning of reflectors have the disadvantage that most reflector manufacturers do not have hydroforming or spinning capabilities in-house and must rely on outside contractors with that capability to form the reflectors. Another disadvantage of reflectors machine-formed into three-dimensional curved shapes, as by die-drawing, hydroforming or spinning, is that the reflective finish on the reflector must be applied in secondary operations, usually by polishing and anodizing. Using a press brake to successively bend the sheet of material has the drawback that many manufacturing steps or forming operations are required to form the many planar facets that define the reflector shape. Additionally, the series of planar facets formed by press brake forming operations do not provide a substantially continuous curve on the inner reflective surfaces of the sheet panels that may be required to create a certain light distribution pattern. It will also be appreciated by those skilled in the art that after reflectors are formed into their three-dimensional shapes through the methods above, significant warehouse space may be required to store the many reflector shapes that may be used. Lastly, multi-part reflectors suffer from the disadvantage that they may require storage and inventory of many different reflector parts and fastening hardware, as well as significant off-line subassembly prior to final fabrication of the three-dimensional reflector.
Thus, there is a need for a self-standing reflector and method of making same that allows the reflector to be formed relatively easily and consistently from a single sheet of reflective material.
There is also a need for a self-standing reflector and method of making that allows the reflector to be rapidly formed from a single sheet of reflective material in relatively few manufacturing steps or forming operations.
There is yet another need for a self-standing reflector and method of making same that allows the reflector to be made from a single sheet of reflective material without requiring additional fastening hardware or subassembly work to form the assembled reflector.
There is also a need for a self-standing reflector and method of making same that allows the reflector to be formed from a single sheet of reflective material relatively quickly as needed at the time and place of luminaire fabrication, thereby reducing the warehouse space necessary to store many different reflector shapes.
There is yet also a need for a self-standing reflector and method of making same that allows the reflector to be formed from a single sheet of reflective material with substantially continuous curves on the inner reflective surfaces of the reflector and retained in a predetermined three-dimensional shape.